CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

InterFoam with boussinesq approximation

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   March 28, 2007, 09:35
Default Hello, I've been trying to
  #1
sinusmontis
Guest
 
Posts: n/a
Hello,

I've been trying to implement the boussinesq approximation into two phase solver interFoam. I have implemented density as a temperature dependent function in the twoPhaseMixture class and added
solve
(
fvm::ddt(T)
+ fvm::div(phi,T)
- fvm::laplacian(DT, T)
);

as the "energy" equation to be solved within the PISO-loop.

As the test case I use a right circular cylinder half filled with the liquid as a axis symmetric simulation (same setup has been used for isothermal simulation and working perfect). Gravity is acting along the symmetry axis and the contact between the liquid and wall is 90, so the liquid is at rest and no motion is induced by capillary forces.

I'm encountering a increase of the liquid fraction during the simulation when the wall that touches the contact line heats up the liquid.
To verify the cause of the phenomena I did some tests. When gravity is turned off and only diffusive terms play a role the liquid/gas ratio stays constant and one can observe the diffusive temperature transport in the liquid and gas. With gravity turned on and only heating the part of the wall that is in contact with the gas produces nice convection/diffusion transport in the gas phase and no change in the liquid/gas ratio is observed.

I'm guessing that the additional density gradient near the surface accounts for additional buoyancy with is not balanced by sigma*k (surface tension * curvature) which causes some flux normal to the liquid/gas interface which is then adjusted by the gamma equation, causing extra liquid volume.

I've tried to adjust the energy equation to account for no convective fluxes across the liquid/gas interface in same manner as in the gamma equation, but without any luck.

Unfortunately I'm out of ideas how to overcome this problem. Did anyone already implement two phase flow with boussinesq approximation?

I would real appreciate if anyone could give me a hint where to look at or point me to some papers that discuss the implementation of the boussinesq approximation in a two phase VOF-code.

Thanks,

Malte
  Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Boussinesq approximation Abdul Aziz Jaafar Main CFD Forum 6 August 15, 2014 10:17
Boussinesq approximation Joshua CD-adapco 0 July 9, 2008 11:13
boussinesq approximation jamal FLUENT 2 March 25, 2008 09:57
Boussinesq approximation Volker Phoenics 0 September 5, 2003 15:48
Boussinesq approximation again Gabriel Main CFD Forum 3 May 11, 2000 09:24


All times are GMT -4. The time now is 02:19.